Liquid crystal display and method for manufacturing the same

ABSTRACT

Disclosed herein are a liquid crystal display (LCD) device and a method for manufacturing the same, capable of preventing problems (i.e., movement of balls, damage to the surfaces that face spacers upon application of predetermined pressure, and variation in cell gap) associated with the use of the ball spacers. The liquid crystal display device includes a first substrate and a second substrate facing each other, a spacer formed on the first substrate, wherein the spacer includes a plurality of balls and a solid to aggregate the balls together and adhere the balls to the first substrate, a hard coating layer formed on the second substrate facing the spacer, and a liquid crystal layer filled between the first substrate and the second substrate.

This application claims the benefit of Korean Patent Application No.2007-100349, filed on Oct. 5, 2007, which is hereby incorporated byreference as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a liquid crystal display (LCD) device.More particularly, the present invention relates to a liquid crystaldisplay (LCD) device and a method for manufacturing the same, capable ofpreventing problems (i.e., movement of balls, damage to the surfacesthat face spacers upon application of predetermined pressure, andvariation in cell gap) associated with the use of the ball spacers.

2. Discussion of the Related Art

With the progress of an information-dependent society, the demand forvarious display devices has increased. To meet such a demand, effortshave recently been made to research flat panel display devices such asliquid crystal displays (LCDs), plasma display panels (PDPs),electro-luminescent displays (ELDs) and vacuum fluorescent displays(VFDs). Some types of such flat panel displays are being practicallyapplied to various appliances for display purposes.

Of these, LCDs are currently most widely used as substitutes for cathoderay tubes (CRTs) in association with mobile image display devicesbecause LCDs have the advantages of superior picture quality, lightness,slimness, and low power consumption. Various applications of LCDs arebeing developed in association with not only mobile image displaydevices such as monitors of notebook computers, but also monitors of TVsto receive and display broadcast signals, and monitors of laptopcomputers.

Successful application of such LCDs to diverse image display devicesdepends on whether or not the LCDs can realize desired high picturequality including high resolution, high brightness, large display area,and the like, while maintaining desired characteristics of lightness,slimness and low power consumption.

Hereinafter, a conventional LCD device will be described with referenceto the annexed drawings.

FIG. 1 is a sectional view illustrating a conventional LCD device.

The conventional LCD device comprises a first substrate 1 and a secondsubstrate 2 that face each other, a liquid crystal layer (not shown)filled between the first substrate 1 and the second substrate 2 and acolumn spacer 20 to maintain the thickness of the liquid crystal layer.

The column spacer 20 is arranged in a region provided above a gate line4. That is, the gate line 4 is arranged on the first substrate 1, a gateinsulating film 15 is arranged over the entire surface of the firstsubstrate 1 including the gate line 4, and a passivation film 16 isarranged on the gate insulating film 15.

A black matrix layer 7 is formed on the second substrate 2 to shieldnon-pixel regions (i.e., portions where gate and data lines, and thinfilm transistors are formed) other than pixel regions. In addition, acolor filter layer, comprising R, G and B color filters arranged atrespective pixel regions, is formed on the second substrate 2 includingthe black matrix layer 7. A common electrode 14 is formed over theentire surface of the second substrate 2 including the color filterlayer 8.

The column spacer 20 is formed on the common electrode 14 in a regioncorresponding to the gate line 4. Accordingly, the first and secondsubstrates 1 and 2 are joined together such that the column spacer 20 isarranged above the gate line 4.

The column spacer 20 is formed in an array process performed on thefirst substrate 1 or the second substrate 2. The column spacer 20 isfixedly formed in the form of a column with a certain height on thepredetermined substrate.

The column spacer 20 is fixed in a specific position. Accordingly, it isadvantageous that the column spacer 20 does not move and thus has nonegative effect on the flow of liquid crystals, when the liquid crystalsare dropped for the formation of the liquid crystal layer. However, thecolumn spacer has a large area in contact with the correspondingsubstrate, thus disadvantageously causing display defects, e.g., touchdefects.

SUMMARY OF THE INVENTION

A liquid crystal display device comprises: a first substrate and asecond substrate facing each other; a spacer formed on the firstsubstrate, wherein the spacer comprises a plurality of balls and a solidto aggregate the balls together and adhere the balls to the firstsubstrate; a hard coating layer formed on the second substrate facingthe spacer; and a liquid crystal layer filled between the firstsubstrate and the second substrate.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 is a sectional view illustrating a conventional liquid crystaldisplay device;

FIG. 2 is a sectional view illustrating a liquid crystal display devicecomprising a ball spacer;

FIG. 3 is a sectional view illustrating a phenomenon in which a ballspacer is embedded in the substrate surface facing the spacer, when theball spacer is used;

FIG. 4 is a sectional view illustrating a liquid crystal display deviceaccording to a first embodiment of the present invention;

FIG. 5 is a sectional view illustrating a liquid crystal display deviceaccording to a second embodiment of the present invention;

FIG. 6 is a plan view illustrating a liquid crystal display deviceaccording to an embodiment of the present invention;

FIG. 7 is a sectional view illustrating the structure of the liquidcrystal display device, taken along the line II-II′ of FIG. 6; and

FIG. 8 is a schematic view illustrating an inkjet system for theformation of the spacer.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, an LCD device and a method for manufacturing the sameaccording to the present invention will be described with reference tothe annexed drawings.

FIG. 2 is a sectional view illustrating a liquid crystal display devicecomprising a ball spacer.

As shown in FIG. 2, in the liquid crystal display device using the ballspacer, a ball spacer 55 is arranged on the outermost surface of a colorfilter array 500 which comprises a black matrix layer 51, a color filterlayer 52, an overcoat layer 53 and an alignment film 54 arranged on asecond substrate 50 in this order.

Recently, methods in which the ball spacer 55 is dotted through anink-jetting technique in a desired position have been suggested. Inaccordance with these methods, after the ball spacer 55 is formed in thedesired position, it often moves from the initial position due toexternal force applied during the formation process or an impact appliedin use. Accordingly, efforts have been made to fix the ball spacer 55 inthe desired portion.

FIG. 3 is a sectional view illustrating a phenomenon in which, when aball spacer is used, the ball spacer is embedded in the substratesurface that faces the spacer.

As shown in FIG. 3, in a case where the ball spacer 55 is formed on thesecond substrate 80 which faces the first substrate 50 provided with thecolor filter array 500, when the ball spacer 55 is fixed on the secondsubstrate 80, a phenomenon, so-called “ball-embedding defect”, in whichthe ball spacer 55 is lodged in the upper surface of the color filterarray 500 which faces the ball spacer 55, because it is harder than thecolor filter array 500, occurs inside the first substrate 50 and thesecond substrate 80, upon application of predetermined pressure to jointhe first substrate 50 to the second substrate 80.

In this case, a decrease in cell gap comparable to the thickness, atwhich the ball spacer 55 is embedded, occurs. As a result, the ballspacer 55 exhibits optical effects different from the panel having anormal cell gap due to a decreased liquid crystal amount. Accordingly,the panel where the ball-embedding defects occur may be considereddefective. In addition, when the ball spacer 55 is embedded in the colorfilter array 500 that faces the ball spacer 55, an area in which theball spacer 55 comes in contact with the color filter array 500 isgreatly increased, and the ball spacer 55 cannot exhibit superiorcontact area decrease effects, as compared to conventional columnspacers. Upon touch operation, in which the first substrate or thesecond substrate 80 is pushed in one direction, the frictional force isincreased and the risk of touch defects is thus increased. As aconsequence, the liquid crystal margin (defined as the range of a liquidcrystal dropping amount at which gravity and touch defects do not occur)of the ball spacer 55 is lower than that of a structure free fromball-embedding defects.

An example where the ball spacer 55 is formed on the second substrate 80is illustrated in FIG. 3. If necessary, the ball spacer 55 may be formedon the first substrate 50 provided with the color filter array 500, andthus come in contact with a thin film transistor array arranged on thefirst substrate 50. In this case, the outermost film of the thin filmtransistor array may include an organic or inorganic insulating film,like a passivation film. The ball-embedding phenomenon shown in FIG. 3may occur in the organic or inorganic insulating film that comes incontact with the ball spacer. As a result, the afore-mentioned problemsmay occur.

Accordingly, a liquid crystal display device and a method formanufacturing the same capable of solving the ball-embedding problem,based on structural approaches, will be illustrated in detail withreference to the annexed drawings.

FIG. 4 is a sectional view illustrating a liquid crystal display deviceaccording to a first embodiment of the present invention.

As shown in FIG. 4, the liquid crystal display device according to thefirst embodiment of the present invention comprises: a thin filmtransistor array substrate 150, and a second substrate 200 comprising acolor filter array that face each other; a liquid crystal layer (notshown) filled between the thin film transistor array substrate 150 andthe color filter array; a plurality of balls 131 arranged on the thinfilm transistor array substrate 150; and a solid 132 to adhere the balls131 to the thin film transistor array substrate 150.

The color filter array comprises a black matrix layer 201 formed in anon-pixel region on the second substrate 200; a color filter layer 202formed on the second substrate 200 including the black matrix layer 201;an overcoat layer 203 formed over the entire surface of the secondsubstrate 200 including the black matrix layer 201 and the color filterlayer 202; and a hard coating layer 211 formed over the overcoat layer203.

The color filter layer 202 and the overcoat layer 203 may be selectivelyomitted. The spacer 130 is arranged in a portion provided within thewidth of the black matrix layer 201 on the thin film transistor arraysubstrate 150. That is, the spacer 130 is formed in the non-pixel regionand fixed by means of a solid 132 for the purpose of preventingmovement.

A second alignment film 204 to define initial alignment of liquidcrystals is further formed on the hard coating layer 211, and a firstalignment film (not shown) is further formed on the thin film transistorarray substrate 150. The formation of the first and second alignmentfilms is optional.

The hard coating layer 211 formed over the entire surface of the secondsubstrate 200 has hardness equivalent or comparable to that of the ball131. In the process of joining the thin film transistor substrate 150 tothe second substrate 200 comprising the color filter array, when thespacer 130 comprising the ball 131 and the solid 132 faces the secondalignment film 204 arranged on the hard coating layer 211, the hardcoating layer 211 can prevent the ball 131 from being embedded in thesecond alignment film 204 as its hardness is comparable to that of theball 131. That is, the ball-embedding phenomenon can be prevented.

Although not shown, the thin film transistor array substrate 150comprises: a plurality of gate lines and a plurality of data lines thatintersect each other to define pixel regions; a plurality of thin filmtransistors formed at respective intersections between the gate linesand the data lines; pixel electrodes and common electrodes alternatelyformed in the pixel regions; a gate insulating film formed between thegate line layer and the data line layer; and a passivation film formedbetween the data line and the pixel electrode (See FIG. 6). In thiscase, the liquid crystal is driven based on an in-plane electric field(horizontal field) applied between the pixel electrode and the commonelectrode. The thin film transistor is electrically connected to thepixel electrode.

If needed, the pixel electrode alone may be formed without the commonelectrode in the pixel region. In this case, a vertical electric fieldmay be applied between the pixel electrode and the common electrode byforming the common electrode over the second substrate 200. In a casewhere the common electrode is made of a transparent electrode materialsuch as indium tin oxide (ITO) or indium zinc oxide (IZO), the commonelectrode may be used as an alternative to the hard coating layer 211.

In addition, the thin film transistor array substrate 150 comprises thefirst substrate and the thin film transistor arranged thereon. Inaddition to the afore-mentioned configuration, the thin film transistorarray may be modified into a variety of forms.

Meanwhile, the spacer 130 is formed in accordance with an ink-jettingmethod which is performed by jetting a spacer-forming material containedin an ink-jet head (not shown) in predetermined portions. Thespacer-forming material comprises about 2 to about 20% by weight of aliquid thermosetting binder (in an uncured state of the solid 132), thesolid 132 (in a cured final state of the liquid thermosetting binder)and the balls 131. In this regard, the balls 131 are not stacked in theform of a laminate, instead being spread over the color filter substrate210 in the form of a monolayer. As shown in FIG. 4, the spacer 130 iscomposed of a single ball 131. Alternatively, the spacer 130 may becomposed of a plurality of balls 131 arranged in a longitudinaldirection. If necessary, as shown in the drawings, the balls 131 may bearranged in both horizontal and vertical directions in the one plane.

In the process of ink-jetting, the spacer-forming material comprisingthe balls for forming the spacer 130 is jetted in the correspondingregion and then cured at about 80 to about 300° C. As a result, thethermosetting binder is cured and then solidified in the form ofaggregates including the plurality of balls, while the solvent isvolatilized.

The solid is an uncured form of the liquid thermosetting binder. Forexample, the solid includes at least one selected from acrylic-based,urethane-based and epoxy-based organic compounds, or a silicone-basedcompound. Specific examples of acrylic compounds include ethylmethacrylate, N-butyl methacrylate, isobutyl methacrylate,dicyclopentanyl methacrylate, benzyl methacrylate, glycidylmethacrylate, 2-hydroxyethyl methacrylate, methacrylic acid isobornylmethacrylate and styrene polymers, and combinations thereof.

The solvent is selected from those that have a boiling point of about 60to about 300° C. For example, glycol ether may be used as the solvent.Examples of useful glycol ethers include propylene glycol methyl ether(PGME), dipropylene glycol methyl ether (DGME), tripropylene glycolmethyl ether (TGME), propylene glycol methyl ether acetate (PGMEA),dipropylene glycol methyl ether acetate (DGMEA), propylene glycoln-propyl ether (PGPE), dipropylene glycol n-propyl ether (DGPE),propylene glycol n-butyl ether (PGBE), dipropylene glycol n-butyl ether(DGBE), tripropylene glycol n-butyl ether (TGBE), propylene glycolphenyl ether (PGPE), propylene glycol diacetate (PGD), dipropyleneglycol dimethyl ether (DGDE), diethylene glycol ethyl ether (DGEE),diethylene glycol methyl ether (DGME), diethylene glycol n-butyl ether(DGBE), diethylene glycol hexyl ether (DGHE), diethylene glycol n-butylether acetate (DGBEA), ethylene glycol propyl ether (EGPE), ethyleneglycol n-butyl ether (EGBE), ethylene glycol hexyl ether (EGHE),ethylene glycol n-butyl ether acetate (EGBEA), triethylene glycol methylether (TGME), triethylene glycol ethyl ether (TGEE), triethylene glycoln-butyl ether (TGBE), ethylene glycol phenyl ether (EGPE) and ethyleneglycol n-butyl ether mixtures (EGBEM).

Preferably, the solvent has a surface tension of 20 to 80 dynes/cm, aviscosity of 1 to 30 cP and a density of 0.8 to 1.2 g/cc at ambienttemperature. Based on these properties, the solvent is volatilized andremoved during curing at about 80 to about 300° C.

In addition, the balls 131 are made of an organic compound e.g.divinylbenzene. The balls 131 can be distinguished from otheringredients, in that the balls are present in the form of a whitepowder, while the solid and the solvent are in a liquid state. Ifnecessary, the balls 131 may be subjected to surface-treatment prior tobeing mixed into the spacer-forming material so that they can bedistinguished from other liquid components.

The process for forming the spacer 130 will be illustrated below. Thespacer-forming material comprising a plurality of balls and a mixedliquid material consisting of a liquid thermosetting binder and asolvent is ink-jetted and then heated. In the process of heating, thesolvent is volatilized, and the liquid thermosetting binder is curedsuch that the balls are aggregated together and fixed on the firstsubstrate, to form a solid. As a consequence, the spacer 130 isobtained.

In this case, the hard coating layer 211, which is formed on the secondsubstrate 200 that faces the spacer 130, may be selectively formed onlyin a region where the spacer 130 is formed. As shown in the drawing, itis more preferable that the hard coating layer 211 be formed over theentire surface of the spacer 130 to reduce the number of masks to beused.

In addition, as illustrated above, by forming the hard coating layer 211that has the same hardness as or a similar hardness to the ball 131, itis possible to prevent touch defects caused by the ball-embeddingphenomenon. As a result, the liquid crystal margin can be increased froma level less than about 0.8% shown in FIG. 3 up to about 5.5%.

Hereinafter, a liquid crystal display device according to a secondembodiment of the present invention will be illustrated with referenceto the annexed drawings.

FIG. 5 is a sectional view illustrating a liquid crystal display deviceaccording to the second embodiment of the present invention.

As shown in FIG. 5, the liquid crystal display device according to thesecond embodiment of the present invention comprises: a thin filmtransistor substrate 150 and a second substrate 200 comprising a colorfilter array that face each other; a liquid crystal layer (not shown)filled between the thin film transistor array substrate 150 and thecolor filter array; a ball 131 arranged on the color filter array; and asolid 132 to adhere the ball 131 to the color filter array.

The liquid crystal display device of the second embodiment is differentfrom that of the first embodiment in that the spacer 130 comprising theball 131 is formed on the second substrate 200. When the spacer 130 isformed on the second substrate 200, a hard coating pattern 110 is formedin a portion corresponding to the spacer 130 on the thin film transistorarray substrate 150 that faces the spacer 130. That is, unlike the hardcoating layer formed over the entire surface of the second substrate inthe first embodiment, the hard coating pattern 110 is at the same levelas a second storage electrode 103 a or a common electrode connectionpattern 104 a made of a transparent electrode material adjacent thereto.That is, the hard coating pattern 110 is formed at the same level as thetransparent electrode (e.g., pixel electrode) adjacent thereto to reducethe number of masks used for forming the same. In addition, the hardcoating pattern 110 must be arranged as the uppermost layer of the thinfilm transistor array substrate 150 that directly comes in contact withthe spacer 130 in order to minimize damage to the surface that faces thespacer 130.

The hard coating pattern 110 is arranged on the gate line 101 and has alength (in a longitudinal direction of the gate line 101) of about 60 toabout 120 μm and a width of about 10 to about 30 μm. If needed, thesecond storage electrode 103 a or the third common connection electrode104 a may be formed such that it overlaps the gate line 101. In thesecases, the hard coating pattern 110 is formed such that it is spacedapart from the second storage electrode 103 a and the third commonconnection electrode 104 a.

The color filter array comprises a black matrix layer 201 formed in anon-pixel region on the second substrate 200; a color filter layer 202formed on the second substrate 200 including the black matrix layer 201;and an overcoat layer 203 formed over the entire surface of the secondsubstrate 200 including the black matrix layer 201 and the color filterlayer 202.

A second alignment film 204 to define initial alignment of liquidcrystals may be further formed on the overcoat layer 203, and a firstalignment film 116 may be further formed over the entire surface of thetop including the uppermost layer (the pixel electrode and the hardcoating pattern 110) of the thin film transistor array substrate 150.The first and second alignment films 116 and 204 are optional. The firstand second alignment films 116 and 204 have thicknesses smaller than thethicknesses (i.e., about 1,000□) of the pixel electrode and the hardcoating pattern 110, thus being hardly affected by variations inthickness. Furthermore, the first and second alignment films 116 and 204are completely baked prior to joining of both substrates, thusminimizing deformation caused by applied pressure. Accordingly, thesurface variation of the first alignment film 116 that directly comes incontact with the spacer 130 is considered to be only slight andnegligible.

The formation of the spacer 130 is performed in accordance with theink-jetting method illustrated in the first embodiment, and constituentcomponents of the spacer 130 are the same as in the first embodiment.Accordingly, a detailed explanation thereof is omitted.

Hereinafter, the structure provided on the first substrate will bedescribed in detail with reference to the annexed drawings. Theconfiguration of the first substrate is applicable to the first andsecond embodiments.

FIG. 6 is a plan view illustrating a liquid crystal display device ofthe present invention. FIG. 7 is a sectional view taken along the lineII-II′ of FIG. 6.

A plurality of gate lines 101 and a plurality of data lines 102 arearranged on the first substrate 100, such that the gate lines 101 andthe data lines 102 intersect each other, to define pixel regions. Inaddition, common lines 111 are arranged on the first substrate 100 suchthat the common lines extend in parallel to the gate lines 101.

In addition, thin film transistors are located at respectiveintersections of the data lines 101 and the gate lines 102. Each thinfilm transistor includes: a gate electrode 101 a protruding from theassociated gate line 101; a gate insulating film 114 formed over theentire surface of the first substrate 100 including the gate electrodes101 a, the gate lines 101 and the common lines 101; a “U”-shaped sourceelectrode 102 a and a drain electrode 102 b arranged at both sides ofthe gate electrode 101 a such that the drain electrode 102 b ispartially located in the “U”-shaped source electrode 102 a; andsemiconductor layers 105 (105 a, 105 b) arranged in regions includingportions under the source electrode 102 a and the drain electrode 102 b,and channel portions between the source electrode 102 a and the drainelectrode 102 b. The semiconductor layers 105 include an amorphoussilicon layer 105 a and an impurity semiconductor layer (n+ layer) 105 barranged thereon. The impurity semiconductor layer 105 b is formed byremoving the channel region present between the source electrode 102 aand the drain electrode 102 b. The shape of the source electrode 102 ais not limited to the “U”-shape and may be “-”- or “L”-shaped.

The data line 102 has a central bent portion at each sub-pixel such thatthe data line 102 forms a zigzag line. The common line 111 is integrallyformed with a storage electrode 111 a at each pixel and the storageelectrode 111 a is connected to a common electrode connection electrode111 b which lies adjacent to both sides of the data line 102 andprotrudes in parallel to the data line 102. As mentioned above, the dataline 102 crosses the gate line 101 and has a bent portion at each pixel.Exemplary embodiments of the present invention are not limited theretoand the data line may perpendicularly cross the gate line, or may betilted at a predetermined angle with respect to the gate line. In theillustrated drawings, the reason for imparting the bent portion to thedata line 102 at each pixel is that the common electrode 104 and thepixel electrode 103 extend in parallel to the data line, and avertically symmetrical electric field is thus generated, on the basis ofthe bent portion, which allows for orientation of liquid crystals indifferent directions and thus leads to an improvement in viewing angle.

The common electrode 104 and the pixel electrode 103 are made oftransparent electrodes at the same level in pixel regions and havealternately arranged portions. The common electrode 104 is partiallyoverlapped with the common electrode connection electrode 111 b arrangedtherebeneath. A second common electrode connection electrode 111 c whichextends in parallel to the gate line 101 has, as an electrical contact,a second contact portion 117 b which passes through the passivation film115 and the gate insulating film 114 interposed between the commonelectrode 104 and the second common electrode connection electrode 111c.

In addition, the pixel electrode 103 is branched from the second storageelectrode 103 a overlapping the first storage electrode 111 a, and has,as an electrical contact, a first contact portion 117 a which passesthrough the passivation film 115 interposed between the pixel electrode103 and the drain electrode 102 b.

Hereinafter, a method for manufacturing the structure of the firstsubstrate 100 including the thin film transistors, the common electrodesand the pixel electrodes will be illustrated in detail.

A metal such as Mo, Al or Cr is deposited on a first substrate 100 andis then patterned through photolithographic processes to simultaneouslyform a plurality of gate lines 101, gate electrodes 101 a, common lines111 extending parallel to the gate lines 101, first storage electrodes111 a integrally formed with the common lines 111, and first commonelectrodes 111 b and second common electrodes 111 c branched from thefirst storage electrodes 111 a and protruded in pixel regions. At thistime, the gate electrodes 101 a are formed in predetermined positionsprovided by pixel regions such that they are protruded from the gatelines 201, and the first storage electrodes 111 a, the first commonconnection electrodes 111 b and the second common connection electrodes111 c are formed in the boundaries between adjacent pixel regions.

Then, an inorganic insulating material is deposited over the firstsubstrate 100 provided with the gate lines 101, the common lines 111,the gate electrodes 101 a, the first storage electrodes 111 a, and thefirst and second common connection electrodes 111 b and 111 c, to form agate insulating film 114.

Subsequently, an amorphous silicon layer 105 a and an impuritysemiconductor layer 105 b are sequentially deposited on the gateinsulating film 114.

A metal such as Mo, Al or Cr is deposited on the resulting structure anda photosensitive film is applied thereto. For example, thephotosensitive film may be a negative photosensitive film.

The portions where the data lines, source electrodes and drainelectrodes are formed define a light-transmission part, the channelportions of the semiconductor layers define a light-semi-transmissionpart, and the remaining portions defined a light-shielding part. In thisregard, masks (not shown) defined as the light-shielding part arepositioned on the photosensitive film.

Subsequently, the photosensitive film is exposed to light and is thendeveloped through the masks, to form a first photosensitive film patternsuch that the portions provided by the light-transmission part remainun-etched, the portions provided by the light-semi-transmission part arepartially removed, and the portions provided by the light-shielding partare completely removed. The metal material is patterned using the firstphotosensitive film pattern (not shown) in accordance withphotolithographic processes. The first photosensitive film patternincludes a first pattern which has a bent portion in each pixel region,while crossing the gate line 101, and a second pattern (corresponding tothe light-transmission part where the source and drain electrodes areformed, including the light-semi-transmission part of the masks) whichis connected to the first pattern at the intersection of the gate line101 and extends toward the pixel region. After the patterning of themetal using the first photosensitive film pattern, data lines 102 whichcross the gate lines 101 and have a bent portion at respective pixelregions are formed, and dummy patterns (not shown) connected to the datalines 102 are formed in portions corresponding to the second pattern.

Subsequently, the impurity semiconductor layer 105 b and the amorphoussilicon layer 105 a are primarily selectively removed using the datalines 102 and the dummy patterns as masks.

Subsequently, with respect to the first photosensitive film pattern (notshown), the first photosensitive film pattern is subjected to ashingsuch that the photosensitive film provided by thelight-semi-transmission part of the mask which has a relatively smallerthickness is removed, to form a second photosensitive film pattern (notshown).

Subsequently, the portions, where the metal material (located in thesame layer as the data line 102) of the dummy pattern and the impuritysemiconductor layer 105 b are exposed, are selectively removed using thesecond photosensitive film pattern as a mask, to form source electrodes102 a and drain electrodes 102 b and to pattern the impuritysemiconductor layer 105 b arranged thereunder. In this process, theimpurity semiconductor layer 105 b interposed between the sourceelectrode 102 a and the drain electrode 102 b is removed. The removedregion is defined as a channel portion. The source electrode 102 a isformed in the “U” shape that protrudes from the data line 102 toward thepixel region. The drain electrode 102 b is spaced apart from the sourceelectrode 102 a by a predetermined distance and is partially embedded inthe “U” form of the source electrode 102 a.

Subsequently, a passivation film 115 is deposited over the gateinsulating film 114 provided with the data lines 102, the sourceelectrodes 102 a and the drain electrodes 102 b. At this time, thepassivation film 115 is generally made of an inorganic material e.g.,SiN_(x). In order to increase an aperture ratio of liquid crystal cells,low dielectric organic materials such as benzocyclobutene (BCB), spin onglass (SOG) and acryl may be used.

Subsequently, a portion of the passivation film 115 arranged on thedrain electrode 102 b is selectively etched to form a first contactportion 117 a, and the passivation film 115 and the gate insulating film114 provided in predetermined portions on the second common connectionelectrode 111 c are selectively removed to form a second contact portion117 b.

Subsequently, a transparent electrode is deposited over the passivationfilm 115 including the first and second contact portions 117 a and 117 band is then selectively removed, to form a plurality of commonelectrodes 104 which are partially overlapped with the common electrodeconnection electrodes 111 b at respective pixels and spaced apart fromone another, third common connection electrodes 104 a overlapping thesecond common connection electrodes 111 c and connecting the commonelectrodes 104 in pixel regions of the common electrodes 104, and aplurality of pixel electrodes 103 alternating with the common electrodes104.

Subsequently, a first alignment film 116 is formed over the entiresurface of the passivation film 115 including the pixel electrode 103and the common electrodes 104.

FIG. 8 is a schematic view illustrating an inkjet system used to formthe spacers according to the present invention.

First, when a gas, e.g., nitrogen is injected into a supply tank 300filled with a spacer-forming material wherein balls 131 are mixed with aliquid material 135 consisting of a liquid thermosetting binder and asolvent, the supply tank 300 undergoes an increase in internal pressure,which causes the spacer-forming material present in the supply tank 300to be supplied through a pipe 320 into a plurality of inkjet heads 400.

The spacer-forming material supplied into the inkjet head 400 is sprayedthrough a nozzle (not shown) present inside the inkjet head 400 and isdischarged in the predetermined portions of the second alignment film204 (not shown in FIG. 10) arranged over the black matrix layer 201 (notshown in FIG. 10) on the second substrate 200. In this dischargeprocess, since the spacer-forming material has slight spreadability andis oblate, it is cured through a heating process to form a spacer 130.

The pipe 320 is connected with a supply pipe (not shown) in the inkjethead 400. Thus, the spacer-forming material supplied via the pipe 320flows through the supply pipe in the head 400. At this time, when avoltage applier 480 applies a voltage to a piezoelectric device (notshown), the piezoelectric device causes mechanical deformation, thuscontracting the passage of the supply pipe and allowing thespacer-forming material to be discharged through the opposite nozzle(not shown).

At this time, at least one of the head 400 and a substrate stage 210 maybe moved in a predetermined direction. Accordingly, when a large area ofthe second substrate 200 is provided, the second substrate 200 isdivided into portions and ink-jet processes through the heads 400provided in the ink-jet system are carried out in respective portions.

An example where the liquid crystal display device according to thepresent invention employs an in-plane switching (IPS) mode wasillustrated with reference to the drawings. In the cases where theafore-mentioned spacer is applied to TN-mode liquid crystal displaydevices in which pixel electrodes are formed at respective pixels andcommon electrodes are further formed on the second substrate, it ispossible to obtain the same effects as in the example.

The liquid crystal display device and the method for manufacturing thesame have the following advantages.

First, since the spacers are made of balls with a small area in contactwith the substrate that faces the spacers and a solid to adhere theballs to the substrate, they can reduce the frictional force due to thesmall area in contact with the substrate surface and allow twosubstrates, which are shifted upon touch operation, to rapidly return totheir original states, thus preventing touch defects.

Second, the spacers are formed using a material comprising a solid toadhere the balls to the substrate surface where the spacers are to beformed, thus being not movable in the space between the two substrates,instead being fixed in the initial position, thereby preventing lightleakage caused by movement of the balls.

Third, a hard coating layer or a hard coating pattern formed on thesubstrate surface that faces ball spacers functions to prevent problems(i.e., damage to the substrate surface that faces the spacers, and theball spacer-embedding phenomenon) associated with the use of the ballspacers that are harder than organic or inorganic insulating films.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. A liquid crystal display device comprising: a first substrate and asecond substrate facing each other; a gate line and a data line disposedon the first substrate such that the gate line and the data lineintersect each other to define a pixel region; a thin film transistordisposed at an intersection between the gate line and the data line onthe first substrate; a black matrix layer disposed on the secondsubstrate in a portion corresponding to the gate line and the data line;a color filter array disposed on the second substrate including theblack matrix layer; a spacer disposed on the color filter array in apredetermined portion provided within the black matrix layer, whereinthe spacer comprises a plurality of balls and a solid to aggregate theballs together and adhere the balls to the color filter array; a pixelelectrode electrically connected to the thin film transistor formed inthe pixel region; a hard coating pattern disposed on the gate linefacing the spacer, being separate from the pixel electrode, wherein thehard coating pattern and the pixel electrode are at the same layer; anda liquid crystal layer filled between the first substrate and the secondsubstrate.